2200LZJE-HO-C6-N_2013.12.
Chapter 6 Troubleshooting
Compound 2-stage Screw Compressor 2016**C
6-11
Symptom
Direct cause
Root cause
Action
12 Compressor
generates
abnormal
vibration
and/or
sound.
Foreign substances
entering the
compressor
Welding spatter,
etc. flowing from
upstream side
Check suction strainer and/or oil
filters. Replace element if defective.
Overhaul the compressor.
Collect foreign substances and
identify their sources. Then take
necessary actions.
Tools and/or waste
cloth left
uncollected after
overhauling
Damaged thrust
bearings.
Deterioration over
time (operated
beyond
recommended time
of replacement)
The time for replacement depends
largely on operating conditions (low
pressure or high intermediate
pressure will make the life shorter,
etc.) and/or oil management
conditions. In case of a typical
refrigeration application which
basically operates in a stable
continuous mode, inspect and
replace them every 40,000 hours or
5 years, whichever comes first.
For details, see Chapter 5, 5.2.3 in
this manual.
Operation with
liquid flow-back
Refer to causes of "Liquid flow-back
during startup" and "Liquid
flow-back during operation" in item
12.
Entry of foreign
substances
Refer to causes of "Foreign
substances entering the
compressor" above.
Excessive thrust
stress other than
above
・
High suction
pressure/intermed
iate pressure
exceeding the
level set by
operating
conditions
Re-examine operating conditions,
and improve if possible.
If difficult to improve, review
maintenance interval.
Faulty assembly
* Lock nuts
tightened
insufficiently, lock
washer tab not
bended, rotation
stopper not set to
thrust bearing
gland, gland not
assembled, etc.
Tighten lock nuts by using specified
torque or torque angle (see Chapter
7, "7.3 Tightening Torques for Bolts
and Nuts" in this manual).
Be sure to record data on the
assembly check sheet to prevent
omission of work steps.
Resonance
vibration
This occurs when
the frequency of
vibration comes
close to the natural
frequency of any
component in the
entire vibrating
system, including
pipes and supports.
In many cases, this symptom is
caused by change in installation
environment (such as change in
piping routes or additive installation
of devices within machine room, oil
level change, etc.)
→
If occurrence of resonance
vibration is a suspected, contact our
service center.